WEST MIFFLIN (AP) — Officials at a western Pennsylvania amusement park say a sensor issue caused a roller coaster to stop mid-ride, but that the riders on board were rescued without incident.

It happened Tuesday afternoon on the “Phantom’s Revenge” ride at Kennywood Amusement Park near Pittsburgh. Officials say the ride automatically stopped in the middle of the first big hill after the sensor malfunctioned.

Kennywood personnel then walked the riders down a stairwell along the coaster’s lift hill, opting not to make them wait while technicians checked out the problem.